Couple thoughts on this........First -maybe to keep target in immediate view and not lose target view or range.Second-primary weapon is still up to use as a defense tool to strikethird-maybe faster to move your arm to that position than attempting to remove from position- then go to secondary weapon and if not needed retry clearing again.WW

Yeah, looking down the sight here is less a matter of keeping the eye on the enemy, although that is important, and more a matter of making sure the rifle stays in the proper position so that the sling technique works.